Departament de Microbiologia 


MICROBIOLOGY OF
 WATER RELATED TO
 THE HEALTH (MARS)


Francisco Lucena
Anicet R. Blanch
Cristina Garcia
Joan Jofre
Maite Muniesa


MAITE MUNIESA


contact
bio
research
publications


RESEARCH PROJECTS



1) Phage-mediated mobility of virulence factors in pathogenic Escherichia coli

Pathogenic E. coli is a food-borne microorganism, causing severe intestinal diseases. This pathogen produce diverse pathogenic factors which confers its virulence. Among others, the most relevant is the Shiga toxin (Stx), encoded by stx. The stx is located within temperate bacterial viruses (bacteriophages or Stx phages). The viral DNA is inserted within the bacterial chromosome, therefore the stx is also located within the bacterial DNA and the Shiga toxin can be produced by the bacteria. Activation of the bacteriophage lytic cycle causes an increase in the Stx production in the host strain and moreover, Stx phages can transfer the stx to non-producing Straits by transduction. The Studies conducted are focused in the prevalence and abundance of Stx phages in the environment and food, the phages ability to transduce the stx and the mechanisms of activation of the lytic cycle of the bacteriophages and the stx transfer among bacteria. Besides stx, other virulence factors in pathogenic E. coli are also bacteriophage encoded. Among these, the relevant Cytolethal distending toxin (CDT), and other effectors proteins of the type three secretion system. These studies are focuses in the prevalence and characterization of phages encoding these virulence genes and their mechanisms of transduction.


Projects
BMC20000549 2000, Colired-0157, Ramón y Cajal, AGL2006-01566/ALI, AGL2009-07576/ALI, AGL2012-30880, FAGOMA


Staff
Dr. Maite Muniesa


Predocs
Maryuri Andrea Brown
Àlex Martínez
Pablo Quirós


Technicians
Aiora Aregita




2) Role of bacteriophages in the transmission of antibiotic resistances

Antibiotic resistance is an increasing global problem, due to the difficulties of the use of antibiotics for treating infectious diseases. Many antibiotic resistance genes are though to be originated in microorganisms in the environment, and from there have been transferred to other bacteria through mobile genetic elements. Among these plasmids and transposons have been described. In this study, efforts are conducted to study the role of another element, bacteriophages. Since bacteriophages have a great persistence in the environment, it is thought that they could act as vectors for mobilization of antibiotic resistance genes outside the clinical settings.

Their prevalence is studied using quantitative real time techniques and their ability to transfer the antibiotic resistance is evaluated through transduction studies. We have been working in resistance to β-lactam antibiotics in enterobacteria and in Staphylococcus aureus. The abundance of resistance genes detected in phage DNA isolated from wastewater and river water in our genographical area and in other aras as well as directly in human faeces, and it supports the role of phages as reservoir of antibiotic resistance genes in the environment. In addition we are evaluating the role of climate change in the evolution of the antibiotic resistances in environmental bacteria .


Projects
RecerCaixa, Fundación Ramón Areces, FAGOMA, REEDEX


Staff
Dr. Maite Muniesa
Dr. Joan Jofre


Predocs
William Calero


Technicians
Aiora Aregita




3) Bacteriophages of Bacteroides as fecal viral indicators applied to microbial source tracking in fecally polluted water samples

The determination of the levels of fecal pollution in surface water samples allow stimation of the associated health risks, since they are different regarding their human or animal origin. The determination of the fecal source allow targeted, efficient and cost-effective remediation efforts in the catchment and will solve legal problems derived from this pollution. Common microbial indicators, as E. coli or enterococci, did not introduce the necessary information for the detection of the source of fecal pollution. With this purpose, chemical and microbiological (microbial source tracking (MST)) methods have been developed for discrimination of a specific fecal source. The research developed in our group is to introduce new proposals of microbial indicators and also the development of methodological tools based in the detection of specific microorganismes or in molecular techniques needed for their detection. Moreover, new methodological approach combine the new proposed indicators for MST, specific for the diverse fecal origins of pollution with the traditional indicators that give information about the amount of pollution but non-specific for the fecal source. We are evaluating the use of inductive learning systems by computer to select the most suitable combination of methodologies in order to develop predictive models. The persistence and prevalence of the different MST indicators in the environment has been evaluated as well as the persistence to different treatments applied in water samples.

Among the most relevant indicators analyzed, several Bifidobacterium species, specifically associated to a given host (fecal source) and bacteriophages infecting selected host strains of Bacteroides species are used as markers to track fecal contaminants in water. The analysis of bacteriophages infecting Bacteroides are performed by a standard methodology (ISO) which has also been developed within our group of research.


Projects
FP-7, AQUAVALENS


Staff
Dra. Maite Muniesa
Dr. Joan Jofre
Dr. Anicet Blanch
Dr. Francisco Lucena
Dra. Cristina García Aljaro


Postdocs
Elisenda Ballesté


Predocs
Marta Gómez Doñate


Technicians
Aiora Aregita